The Food and Drug Administration is seeking details from manufacturers of antimicrobials that are used in livestock. It's part of an effort to curb development of antibiotic-resistant “superbugs” that make drugs used in both animals and humans no longer effective.

The agency issued draft guidance (PDF) on Tuesday that would require drug companies that sell antimicrobial medicines for use in food-producing animals to collect and report sales data according to the species. That would determine the extent at which their products are used specifically in chickens, turkeys, cattle and pigs.

For years, public health advocates have pointed to a link between widespread use of antibiotic medications and the rising number of pathogens that are resistant to such medicines. The Centers for Disease Control and Prevention have over the last several years warned healthcare professionals against overprescribing antibiotics. An estimated 2 million infections that occur in the U.S. each year are related to antibiotic resistance, according to the CDC, resulting in an estimated 23,000 deaths and around $20 billion annually in healthcare costs.

Concerns over antimicrobial overuse prompted the White House in March to release a five-year action plan (PDF) to combat antimicrobial-resistant illness that called for rapid surveillance to identify antimicrobial-resistant disease outbreaks and a greater focus on developing new antibiotics.

While aspects of the plan address the need to reduce the use of antibiotics in healthcare, critics say it falls short in addressing the widespread use of antibiotic medications within livestock, some of which are used for both animals and humans.

Those drugs have long been included in animal feed and drinking water as a means of staving off infection, as well as to help animals gain weight without having to increase their food. An estimated 70% of medically important antibiotics are sold for food animals, according to the Pew Charitable Trusts. Nearly 30 million pounds of such drugs were sold in the U.S. in 2011 for meat and poultry production, according to the FDA.

The proposed rule would expand current regulations in place since 2008. Drugmakers annually report the amount of antimicrobial medicines sold and distributed to livestock. The FDA, in turn, makes that information public in its own annual report. The draft guidance would also require the FDA to publish its report no later than Dec. 31 of the following year.

Avinash Kar, an attorney with the Natural Resources Defense Council, called the proposed guidance “a modest step forward,” saying more data was needed to get an accurate picture of the use of antibiotics on farms.

“This is an estimate,” he said. “It's somewhat helpful, it will give us some idea as to the level of use in different species, but we don't really have information on actual use.”

In 2013, the FDA issued guidelines that required companies that produce antibiotics used in livestock to voluntarily remove any animal-growth references from their labeling for medicines deemed medically important to humans. The largest drugmakers of such products, Eli Lilly & Co. subsidiary Elanco and Zoetis, came out in support of the rule at the time, stating they planned to voluntarily limit labeling to reflect their antibiotics should be used for therapeutic purposes.

“Consistent with data collection objectives outlined in the Administration's National Strategy for Combating Antibiotic-Resistant Bacteria, this proposed rule is a step toward providing more detailed information to the FDA and the public on changes in antimicrobial sales and distribution over time,” said Michael Taylor, FDA deputy commissioner for foods and veterinary medicine, in a released statement. “We plan further actions to complete the task.”

A comment period for the proposed rule will remain open over the next 90 days.